Chapter 2 Post-Test

This activity contains 33 questions.

The drawings of atoms in your textbook are actually based on the "planetary model" of what an atom looks like. If a three-dimensional model of an atom could be constructed that is as big as the room you are sitting in, most of the atom's volume would be occupied by ______.

 the electrons the nucleus empty space the neutrons the protons

Before the nature of atoms was known, many men (known as alchemists) tried to turn iron into gold. However, none of them ever succeeded. If you could truly turn iron into gold, how would you do it?

 by adding neutrons to the nuclei of the iron atoms by allowing the iron to undergo a chemical reaction with oxygen by melting the iron and mixing it with melted silver by inserting protons into the nuclei of the iron atoms by bombarding the nucleus with additional electrons

The atomic number of carbon is 6. A neutral carbon atom has __________ protons and __________ electrons.

 3; 3 6; 0 6; 3 6; 6 6; 12

If you examined the human body and the crust of Earth, which of the following combinations of elements would you find were MOST common?

 Si, O, H, C H, C, S, O, P Cl, C, H, O, P C, O, He, P, S C, Na, O, N, H

Protons and neutrons are said to have a mass of approximately 1 dalton each. Recall that electrons are thought to have virtually no mass. Therefore, a hydrogen atom (with an atomic number of 1) would have a mass of approximately 1 dalton, and an oxygen atom (with an atomic number of 8) would have a mass of approximately 16 daltons. How much mass would one molecule of water have?

 10 daltons 14 daltons 18 daltons 20 daltons 33 daltons

If the atomic number of an atom is 20, ________.

 the atom is inert, or non-reactive the atom has fewer than 20 electrons the atom has more than 20 electrons the first, second, and third shells of the atom are full

An element with 12 protons, 12 neutrons, and 12 electrons has an atomic number of _____.

 6 12 24 36

Atom A has enough electrons to completely fill three electron shells, and atom B has enough electrons to fill two and a half electron shells. What can you predict from this information?

 Atom B contains more electrons. Atom A has more protons in its nucleus. Atom B is as stable as atom A. Atom A can donate electrons to another atom to create an ionic bond.

Helium has a filled outermost electron shell and thus _________.

 is very reactive will form ionic bonds has more electrons than protons is unreactive

A cell is to an organ as _______ is to a molecule.

 an atom a nucleus a bond a proton

What happens when a water molecule is formed?

 Two ions are generated that are attracted to each other. The oxygen atom takes on a partial negative charge, and the hydrogen atoms take on a partial positive charge. Two atoms of hydrogen donate their single electrons to an oxygen atom. Two oxygen atoms share electrons with two hydrogens.

Which of the following is formed by the sharing of electrons between two atoms that do NOT differ in electronegativities?

 an ionic bond a hydrogen bond an isotope a polar covalent bond a non-polar covalent bond

If an atom has an atomic number of 7, how many electrons are in the atom's outer shell?

 2 3 4 5 7

Sodium has one electron in its third shell, and fluorine has seven electrons in its second shell. Which of the following statements is an accurate prediction of what will happen when these two elements bond?

 Fluorine will move seven electrons to sodium to create an ionic bond. Sodium and fluorine will hydrogen bond to each other. Sodium will transfer its extra electron to fluorine to create two ions. Sodium and fluorine will share a pair of electrons equally.

Which of the following statements correctly describes the difference between a polar covalent bond and a non-polar covalent bond?

 A polar covalent bond occurs from unequal sharing of electrons, whereas a non-polar covalent bond occurs during equal sharing events. A polar covalent bond occurs between ions, whereas a non-polar covalent bond occurs between atoms. A polar covalent bond occurs when an electron is transferred between two atoms, whereas a non-polar bond occurs with the transfer of a proton. A polar covalent bond occurs when atoms share electron pairs but one electron is left unpaired. A non-polar covalent bond occurs when all the electrons are shared.

A large difference in electronegativity between two atoms is important in regard to what type of bond?

 polar covalent bonds ionic bonds non-polar covalent bonds electron–proton bonds

What does the phrase "Energy always seeks its lowest state" imply about chemical bonds?

 Molecules will tend to break apart into elements. Molecules like water tend to stick to other polar molecules. Most atoms are not reactive because they exist in a their lowest energy state as elements. Atoms tend to fill their electron shells by bonding with each other.

Nitrogen has an atomic number of 7. Given that it can readily form covalent bonds with hydrogen, how many hydrogen atoms would you expect would bond with one nitrogen atom?

 1 2 3 4 5

A small difference in electronegativity between two atoms is important in regard to what type of bond?

 ionic bonds polar covalent bonds electron–proton bonds non-polar covalent bonds

The fundamental difference between covalent bonds and ionic bonds is that in covalent bonds ______, whereas in ionic bonds ______.

 the atoms involved have equal electronegativity; the atoms involved have unequal electronegativity electron pairs are shared; ions are formed the electrons shift from one atom to another; the electrons are shared the outer electron shell becomes filled; the outer shell does not become filled two atoms of different elements bond; two atoms of the same element bond

Look carefully at the following chemical equation. What is INCORRECT about this equation? 3 C + 16 H →3 CH4

 Equations always go from the more complex molecule to the less complex molecule. C atoms will not form chemical bonds with H atoms. The left side of the equation has 16 H, and the right side of the equation has only 12 H. The left side of the equation has 3 C, and the right side of the equation has 12 C. When C atoms bond to H atoms, they form the element Cl.

The symbol 4 H2O represents _________.

 four oxygen atoms and two hydrogens eight water molecules four water molecules two oxygen molecules and eight hydrogens four hydrogen atoms and two oxygen atoms

An atom with an unequal number of protons and electrons is called _____.

 an ion an isotope a molecule an unreactive atom

What number and type of subatomic particles would you expect to see in the nucleus of carbon-14?

 8 protons and 6 neutrons 14 electrons 7 protons and 7 electrons 6 protons and 8 neutrons 14 protons

Why do water molecules stick to other water molecules?

 Water molecules are neutrally charged, and neutral molecules attract. The carbon atoms are attracted to one another. Ionic bonds hold them together. Hydrogen bonds form between water molecules. Covalent bonds hold them together.

If the shape of a molecule is changed, all the following will also change EXCEPT the molecule's __________.

 ability to bind to other molecules chemical properties atomic makeup function

Which of the following materials will dissolve?

 a solvent a solute a solution both a solute and a solvent

Why do salt molecules dissolve in water?

 They form covalent bonds with the water. They have only a few atoms in their molecules. They have a lot of C atoms in their structure. They contain water in their molecular structure. They have atoms with charges on them.

On an early morning walk, you observe beads of water that have formed on the surface of leaves overnight. What property of water allows these beads to form?

 adhesion cohesion non-polarity high specific heat

You may have noticed that unlike many other compounds, the frozen form of water is less dense than the liquid form. What fundamental property of water causes this phenomenon?

 hydrogen bonds non-polar covalent bonding the high specific heat of water surface tension

An acidic solution _________.

 has more hydrogen ions that hydroxide ions has a high pH has more hydroxide ions that hydrogen ions has an equal number of hydrogen and hydroxide ions

You have been given the task of determining which of three known liquids is an acid. You have measured the concentration of hydroxide ions in all three solutions. Solution A has the most hydroxide ions, solution B has the fewest hydroxide ions, and the concentration of solution C is between those of A and B. Which solution is the most acidic?

 solution A solution B solution C Cannot determine an answer given this information.

To neutralize a solution currently measured at pH 1, you need to add _________.

 acid water base vinegar

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